Why the impedance of EIS is differ from actual resistance value

[Akila1993]

Hi @rtimms and Everyone,

I am trying to obtain EIS from pybamm-eis methods, however, the EIS curve is far different from the actual values of resistance 0.025 ohm in the datasheet of the LGM50 cell.

Any comment from the PyBaMM team about this?

Thank you for your consideration and looking forward to hearing.

Below is the code I am using,

import pybammeis
import pybamm
import numpy as np

# DFN with capacitance
model = pybamm.lithium_ion.SPMe(options={"surface form": "differential"}, name="SPMe")
parameter_values = pybamm.ParameterValues("Chen2020")
eis_sim = pybammeis.EISSimulation(model, parameter_values=parameter_values)
# calculate impedance at log-spaced frequencies
eis_sim.solve(np.logspace(-4, 3, 30))
eis_sim.nyquist_plot()

[rtimms]

You can add a contact resistance by setting the option “contact resistance” to “true” and add the parameter “Contact resistance [Ohm]”.